The nature of the interaction Azospirillum-Arabidopsis determine the molecular and morphological changes in root and plant growth promotion

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“…Azospirillum brasilense has been reported to arrest the primary root length and increase the root branching in A. thaliana seedlings exposed at the rhizobacteria for six or seven days. [17][18][19] In the present work, changes in root architecture induced by Azospirillum were determined at shorter exposure times. The results showed that the rhizobacteria arrested primary root growth throughout all incubation times, while the lateral roots number increased after three and six days of exposure to the bacteria from the first day of interaction (Figures 1A&B).…”

“…23,37 In this study we observed that Azospirillum stimulates lateral root development, which is decreased by altering TOR signaling, these observations coincide with the results reported by Méndez-Gómez et al, 2020 18 and Méndez-Gómez et al, 2020. 19 Nanjareddy et al, 22 which show that during the Phaseolus vulgaris-Rhizobium interaction, the inactivation of TOR in beans alters the development of the infection thread, which results in the decrease in the size of the nodule induced by Rhizobium.…”

“…The effect of Azospirillum on plant development has been attributed to the phytohormones it produces, mainly auxins. [16][17][18][19] Auxins are plant growth regulators that participate in practically all plant development processes from reproduction, embryogenesis, hypocotyl elongation, formation of lateral roots and root hairs, besides of regular tropic responses to light and gravity. 20 Indole-3acetic acid (IAA), is the natural auxin that is synthesized in the young shoots of the aerial part of the plant, from where it is distributed to the demanding tissues by two types of transport; one fast and nondirectional through the phloem and the other directional that is carried out cell with the help of influx and efflux carriers; it is known as polar auxin transport (PAT).…”

Participation of Auxin Transport in the Early Response of the Arabidopsis Root System to Inoculation with Azospirillum brasilense

“…The first reports of the effect of Azospirillum on wheat and Arabidopsis showed that the bacteria decreased the length of the root and increased the root branching when the plants interacted with Azospirillum for six and seven days [7,8,[34][35][36]. It seemed to us that this time was too long and that the observed effect was the result of changes occurring at shorter times.…”

“…4). It has been widely reported that Azospirillum brasilense alters the root architecture of a large number of plants and this effect has been attributed to the auxins it produces [1][2][3]7,8,[34][35][36]. In the Azospirillum-Arabidopsis interaction reported by Spaepen et al [7], they evaluated the effect of the auxins produced by the bacteria, when inoculating A. thaliana with two strains of A. brasilense Sp245: one wild-type and the other mutant in auxin biosynthesis (FAJ009).…”